Hydraulic die cutting machine having inertia switch means to control hydraulic operation



June 21, 1966 E. HAAS ETAL 3 56 76 HYDRAULIC DIE CUTTING MACHINE HAVING INERTIA SWITCH MEANS TO CONTROL HYDRAULIC OPERATION Filed Feb. 12, 1965 2 Sheets-Sheet 1 SOLENOID OPERATED ATTORNEYS June 21, 1966 E. HAAS ETAL 3,256,762

HYDRAULIC DIE CUTTING MACHINE HAVING INERTIA SWITCH MEANS TO CONTROL HYDRAULIC OPERATION 2 Sheets-Sheet 2 Filed Feb. 12, 1965 INVENTORS EDWARD KOTTSIEPER EDGAR HAAS M M ATTORN EYS United States Patent HYDRAULIC DIE CUTTING MACIHNE HAVING INERTIA SWITCH MEANS TO CONTROL HY- DRAULIC OPERATION Edgar Haas, New York, N.Y., and Edward Kottsieper, Fairfield, Conn., assignors to Herman Schwabe, Inc., Brooklyn, N.Y., a corporation of New York Filed Feb. 12, 1965, Ser. No. 432,170 8 Claims. (Cl. 83-530) This invention relates to cutting machines, and more particularly to hydraulic cutting machines using loose or moveable dies.

A popular form of cutting machine with which the invention may be used is a machine having a swinging arm or platen. The machine has a table which supports one or more layers of the material to be cut. An operator places one or more loose dies on the material; swings the arm to forward position over the dies and table; and then triggers power means,- preferably hydraulic means, for moving the arm downward to force the dies through the material. The arm is swung sideward by means of a handlewhich usually is providedwith a switch to initiate the cutting operation.

The machine may be provided with a limit switch to arrest and reverse the downward movement of the platen when the material has been cut. For convenience the limit switch has been built into the mechanism of the press, for example, at the cylinder and piston mechanism which forces the platen downward. However, the height of the cutting block on which the material rests may vary, and indeed becomes less as the cutting block is worn with long use. Also, the dies may vary in height. This complicates the use of a limit switch and requires frequent adjustment of a handwheel which is inconveniently located at the very top of the machine.

The general objects of the present invention are to improve cutting presses; to overcome the foregoing difiicul-ty; and to provide an improved cut control means which is small, light, accessible, and easily adjusted. In accordance with a further feature and object, the cut control means responds to the beginning of actual cutting of the material, regardless of the height of the die and of the cutting block. For this purpose we provide an inertia switch on the platen arm, and this responds to the abrupt resistance to further movement which occurs at the transition from free movement to cutting movement of the platen. The circuitry includes relays, and the normal relay delay provides adequate time to complete the cut through thin material.

This normal relay delay may be inadequate when dealing with thick material or, when, as is often the case, multiple plies of material are superposedfor simultaneous cutting. In accordance with a further feature and object of the invention the control circuitry is provided with an adjustable time delay relay, and this is so arranged in relation to the inertia switch that the inertia switch starts the relay, and subsequent expiration of the adjustable time delay of the relay is what reverses the movement of the platen.

To accomplish the foregoing general objects, and other more specific objects which will hereinafter appear, our invention resides in the hydraulic press and electrical control circuitry elements, and their relation one to another as are hereinafter more particularly described in the following specification. The specification is accompanied by drawings in which:

FIG; 1 is a partially sectioned elevation showing the invention applied to a press of the swinging arm type;

FIG. 2 shows the inertia switch, and is an elevation taken'approximately on the line 2-2 of FIG. 1;

3,256,762 Patented June 21, 1966 FIG. 3 is a vertical section taken in the plane of the line 33 of FIG. 2; and

FIG. 4 is an electrical diagram explanatory of the circuitry embodying the inertia switch.

Referring to the drawing, and more particularly to FIG. 1, the press there shown comprises a base 12 supporting a bed 14 and a pedestal or C-frame 16. The bed 114 carries a table 18 on which a cutting block 60 is mounted. This is usually made of wood, but other satisfactory materials have been employed.

The platen 22 forms part of a swinging arm 24 which is mounted on a post 26 which is rotatably received in the C-fra-me 16. The arm 24 may be-swung back and forth by means of a handle Q8, and this preferably embodies a switch 30 which may be used to initiate the cutting operation. The height of the arm 24 may be adjusted, as by means of a hand wheel 32 at the top of the machine. It is shown at maximum elevation, but usually is close to the die 64, to minimize lost motion.

The hydraulic drive means of the press may be conventional. In the present case the base 12 acts also as an oil reservoir. An electric motor 34 drives a-submerged pump 36 which supplies fluid under pressure to the upper end of a cylinder 38 carrying a piston 40 which is connected to post 26 by means of piston rod 42. In the form here shown the cylinder 38 is single acting, and the return or upward movement of the post is produced by means of a pair of return springs 44, one on each side of the cylinder. The upper ends of these springs are fixedly mounted in the machine, and their lower ends are connected to a horizontal bar connected to a downward extension of the piston rod.

The flow of fluid from pump 36 to the upper end of the cylinder is controlled by a solenoid operated hydraulic valve.46, which controls flow through passage 48 to the top end of the cylinder 38. A four way valve is not needed because the cylinder is single-acting. A limit switch 50 is built into the mechanism, and is so arranged in the electrical circuitry that it operates the valve 46 to cause return movement of the piston. Such a limit switch may be used as the sole means for that purpose, but in the present case the limit switch 50 is retained only as a safeguard to prevent the piston from reaching the bottom of the cylinder.

When using the limit switch 50 along the height of the arm 24 would be adjusted by means of wheel 32 as to terminate the downward movement when the die 64 penetrates the material being cut. In the course of work different dies are used, and these may differ in height. The arm then must be set at different heights for the different dies, and his inconvenient to change the adjustmentof the hand wheel 32, which is located at the very top of the machine, and which is a rather heavy adjustment to make.

In the present machine the height of the arm may be adjusted primarily with a view to locating it slightly above the die so as to minimize the lost motion between the platen and the die. The cut is controlled by the inertia switch, and this switch takes effect at the beginning of the cuteven if one die is higher than another, or the number of plies of material is changed, etc.

FIG. 1 as drawn shows the platen in its highest position, and is unrealistic because in actual practice the hand wheel 32 would be used to lower the platen to a height where it just clears the dies intended to be used.

The inertia switch is indicated at 52,-and is located in the press arm 24. It is preferably supplemented by means of an adjustable time delay relay, here shown located in a protective box 54, the timing adjustment being made by means of a dial indicated at 56. There is also a switch 58 which makes the time delay relay operative or inoperative. we call this a selector switch.

In FIG. 1 the table 18 carries a conventional cutting block 60 on which the material 62 which is to be cut is rested. A loose die 64 is placed on the material 62, and is driven through the material when the arm 24 is swung over the die by means of handle 28 and the trigger 30 is operated to initiate the downward or cutting movement. On completion of the cutting movement the arm 24 rises, regardless of whether the trigger 30 is held or released, and the arm then may be turned aside; the die 64 moved to an adjacent position; the arm swung back over the die; and the tiger 30 again operated to blank out another unit from the material 62.

The inertia switch may be described with reference to FIGS. 2 and 3 of the drawing. It comprises a fixed adjustable contact 66 threadedly received in a bracket 68. The adjustmentis locked by means of a lock nut 70. A lower contact 72 is carried on a thin leaf spring 74 which is weighted by means of a heavy metal block 76. The fixed end of spring 74 is anchored at 78 on the raised part 80 of an insulation base-82, which also carries the bracket 68.

It will be understood that the contacts are normally closed. However, when the arm 22 (FIG. 1) engages the die 64 to begin cutting the material, there is an abrupt resistance to continued movement which causes the arm 24 and the switch contact 66 ,(FIG. 3) to hold back, while the weight 76 and switch contact 72 continue moving, thereby momentarily breaking the circuit through the contacts. It will also be evident that the force needed to open the contacts is adjustable by means of the screw 66.

In the machine shown, the die 64 is a loose die which is engaged by the arm, but it will be understood that the same principles would apply to a die mounted on the underside of arm 22, because the inertia switch then would open when the die meets'the material, instead of when the platen meets the die. In either case the inertia switch opens at the beginning of the cutting operation and regardless of the height of the cutting block 60; the thickness of the layer or layers of material 62; the height of the die 64; and the height of the arm.

A preferred form of electrical circuitry and its operation may be described with reference to FIG. 4 of the drawing. The trigger of the handle switch -is indicated at 30. The switch has upper contacts 112 which are opened and lower contacts 114 which are closed when the trigger 30 is operated. The inertia switch is indicated at 52, and the maximum down limit switch is indicated at 50. The time delay dialor adjusting dial for the time delay relay is shown at 56, and the selector switch for making the relay operative or inoperative is shown at 58. The time delay relay itself is marked R4, and its contacts are shown at 132. The solenoid of the solenoid controlled hydraulic valve is indicated at 46.

having normally closed contacts also marked 140. Relay,

R1 is sluggish or has a slight delay compared to relay R3.

The diagram shows the circuit elements connected across a conventional power line, represented by terminals L1 and L2. An overall switch, not shown, may be provided ahead of the terminals.

The operation is first described with the assumption that the material being cut is relatively thin and requires no added time delay, in which case the adjustable time delay relay R4 is left out of the circuit by opening the selector switch 58. Relay R3 is normally energized and its contacts 140 are therefore normally closed. When the operator depresses the handle switch 30 the contacts 112 open and the contacts 114 close. Opening of the upper contacts 112 de-energizes the relay R3, thereby closing its normally open contacts 140. Closing of the lower contacts 114 energizes the relay R1 through a con- ,operate the trigger.

ductor 116, and its contacts 138 open, but only after a slight delay, so that relay R2 is actuated, and is held by its own holding contacts, as described later. The closing of the R2 relay contacts 118 energizes the solenoid 46 of the hydraulic valve, the circuit for this being from line L1 through conductor 122, closed contacts 118, solenoid 46, and back to line L2. This causes the press to operate until the platen strikes the die, whereupon the inertia switch 52 opens.

Relay R1 has a slight fixed delay which need not be adjustable, and which is intended merely to make sure that there will be a momentary flow of current through the contacts 138 and 140 to initiate operation of relay R2. All that is needed is that R1 be slower than R3. The contacts 138 of relay R1 then open, but R2 remains energized through its holding circuit next described.

Relay R2 has the two sets of normally open contacts 118 and 120, and if relay R2 is momentarily energized it then is held energized through a holding circuit which runs from line L1 through conductor 122, inertia switch 52, limit switch 50, relay contacts 120 (then closed) and conductor 128 to relay coil R2 and thence back to line L2.

For thin material the normal relay delay in the described circuit provides sufficient cutting time. The operation takes place as described even if the operator holds the handle switch 30 instead of releasing the same. However, to make anew cut he must release and then again This is so because when he releases the trigger the relay R1 is de-energized and the relay R3 is energized. The contacts of relay R3 open, and the contacts 138 of relay R1 close, but slowly, thereby momentarily de-energizing relay R2, so that its holding circuit is opened, and the machine then is ready for another operation as previously described.

It may be explained that during operation of the press it is desired that the relay R2 be energized solely through the inertia switch 52, and it then must not be energized through the circuit of contacts 138 and 140. These contacts are therefore arranged to operate in alternation. If the operator holds the trigger 30 down, the contacts 138 of relay R1 open, and the contacts 140 of relay R3 open. If the operator releases the trigger-30 quickly after operating the same, the operation for downward movement is the same because the operation of the relays is even faster than the manual release of the trigger, and therefore relay R2 is at least momentarily energized, and then held to complete the cut.

The delay provided by the slight delay relay R1 avoids what is sometimes called racing of contacts when, as here, the contacts 138 and 140 are operated in alternation. The delay of relay R1 provides the desired momentary energization of relay R2 when the contacts 138 and 140 are both closed because of their momentary overlap in operation caused by the slower operation of relay R1. This initiates the energization of solenoid 46, and relay R2 then is held energized by its holding contacts 120, and thus the main contacts 118 are held closed to energize the solenoid 46 until the inertia switch 52 opens.

It may be observed that contacts 112 and 114 of the trigger switch are operated in sequence. That alone provides a delay in proper direction, and therefore the circuitry shown will operate even without making the relay R1 a slow relay. However, it is preferred to make relay R1 a little slower than relay R3 to insure maintenance of an adequate 'orsafe overlap in the operation of therelay contacts 138 and 140.

The operation so far has been described without the adjustable time delay relay R4. When selector switch 58 is closed the relay coil R4 is in shunt with the coil of relay R2, and when energized its contacts 132 provide a shunt circuit through conductors 134 and 136 around the main contacts 118 of relay R2. The result is that when the inertia switch de-energizes the relay R2, the valve solenoid 46 nevertheless remains energized through the shunt circuit 134, 132, 136 until the delay time to which the a delay relay R4 has been set runs out, whereupon the contacts 132 open and valve solenoid 46 is de-energized, permitting the press platen to rise.

It is believed that the construction and method of operation of our improved hydraulic die-cutting machine, as well as the advantages thereof, will be apparent from the foregoing detailed description. It will also be apparent that while we haveshown and described the invention in a preferred form, changes may be made without departing from the scope of the invention, as sought to be defined in the following claims.

We claim:

1. A press comprising a work support, a platen mounted for movement toward or away from the work support, a cutting die therebetween, hydraulic means to move the platen toward the work support to force the die through sheet material positioned on the work support, a solenoid operated valve for said hydraulic means, an electric circuit controlling said valve, an inertia switch mounted on and physically movable with said platen and so arranged that it is operated by inertia when the platen causes the die to begin to cut the material, said switch being so connected in said valve controlling circuit that operation of the switch reverses the movement of the platen after a slight delay adequate for the die to cut through the material.

2. A press comprising a work support, a platen mounted for movement toward or away from the work support, a cutting die therebetween, hydraulic means to move the platen toward the work support to force the die through sheet material positioned on the work support, a solenoid operated valve for said hydraulic means, an electric circuit controlling said valve, an inertia switch mounted on and physically movable with said platen and so arranged that it is operated by inertia when the platen causes the die to begin to cut the material, an adjustable time delay relay in said valve controlling circuit and so arranged in relation to the inertia switch that the inertia switch starts the time delay relay and subsequent expiration of the adjusted time delay of the relay reverses the movement of the platen.

3. A press comprising a work support, a platen mounted for movement toward or away from the work support, a cutting die therebetween, hydraulic means to move the platen toward the work support to force the die through sheet material positioned on the work support, a solenoid operated valve for said hydraulic means, an electric circuit controlling said valve, a manually operable handle switch in said circuit to initiate downward movement of the platen, an inertia switch mounted on and physically movable with said platen and so arranged that it is operated by inertia when the platen causes the die to begin to cut the material, said switch being so connected in said valve controlling circuit that operation of the switch arrests and reverses the movement of the platen after a slight delay adequate for the die to cut through the material, and means whereby this reversal takes place regardless of whether the handle switch is still held down or is released.

4. A press comprising a work support and a platen mounted for movement toward or away from the work support, a cutting die therebetween, hydraulic means to move the platen toward the work support to force the die through sheet material positioned on the work support, a solenoid operated valve for said hydraulic means, an electric circuit controlling said valve, a manually operable handle switch in said circuit to initiate downward move- -ment of the platen, an inertia switch mounted on and physically movable with said platen and so arranged that it is operated by inertia when the platen causes the die to begin to cut the material, an adjustable time delay relay in said valve controlling circuit and so arranged in relation to the inertia switch that the inertia switch starts the time delay relay and subsequent expiration of the ad justed time delay of the relay arrests and reverses the movement of the platen, and means whereby this reversal takes place regardless of whether the handle switch is still held down or is released.

5. A press comprising a work support, a platen mounted for movement toward or away from the work support, a cutting die therebetween, hydraulic means to move the platen toward the work support to force the die through sheet material positioned on the work support, a solenoid operated valve for said hydraulic means, a trigger switch .with closed contacts and open contacts which are sequentially reversed by operation of the trigger, a relay coil in series with said closed contacts, a relay coil in series with said open contacts, said relays respectively having normally open and'normally closed contacts, said contacts being in series with each other and a third relay coil which operates main and holding contacts, said main contacts controlling said solenoid valve, and an inertia switch in series with said holding contacts, said inertia switch being mounted on and physically movable with the platen and so arranged that it is operated by inertia when the platen causes the die to begin to cut the material.

6. A press comprising a work support, a platen mounted for movement toward or away from the work support, a cutting die therebetween, hydraulic means to move the platen toward the work support to force the die through sheet material positioned on the work support, a solenoid operated valve for said hydraulic means, a trigger switch with closed contacts and open contacts which are sequentially reversed by operation of the trigger, a relay coil in series with said closed contacts, a relay coil in series with said open contacts, said relays respectively having normally open and normally closed contacts, said contacts being in series with each other and a third relay coil which operates main and holding contacts, said main contacts controlling said solenoid valve, an inertia switch in series with said holding contacts, said inertia switch being mounted on and physically movable with the platen and so arranged that it is operated by inertia when the platen causes the die to begin to cut the material, an adjustable time delay relay coil in shunt with said third relay coil, the contacts of said time delay relay being in shunt with said main contacts of said third relay, whereby the cutting time may be extended and varied by adjustment of the time delay relay.

7. A press comprising a work support, a platen mounted for movement toward or away from the work support, a cutting die therebetween, hydraulic means to move the platen toward the work support to force the die through sheet material positioned on the work support, a solenoid operated valve for said hydraulic means, a trigger switch with closed contacts and open contacts which are reversed by operation of the trigger, a relay coil in series with said closed contacts, a slower relay coil in series with said open contacts, said relays respectively having normally open and normally closed contacts, said contacts being in series with each other and a third relay coil which operates main and holding contacts, said main contacts controlling said solenoid valve, and an inertia switch in series with said holding contacts, said inertia switch being mounted on and physically movable with the platen and so arranged that it is operated by inertia when the platen causes the die to begin to cut the material.

8. A press comprising a work support, a platen mounted for movement toward or away from the work support, a cutting die therebetween, hydraulic means to move the platen toward the work support to force the die through sheet material positioned on the work support, a solenoid operated valve for said hydraulic means, a trigger switch with closed contacts and open contacts which are reversed by operation of the trigger, a relay coil in series with said closed contacts, a slower relay coil in series with said open contacts, said relays respectively having normally open and normally closed contacts, said contacts with said main contacts of said third relay, whereby the cutting time may be extended and varied by adjustment of the time delay relay.

No references cited.

WILLIAM W. DYER, JRJ, Primary Examiner;

J. M. MEISTER, Assistant Examiner. 

1. A PRESS COMPRISING A WORK SUPPORT, A PLATEN MOUNTED FOR MOVEMENT TOWARD OR AWAY FROM THE WORK SUPPORT, A CUTTING DIE THEREBETWEEN, HYDRAULIC MEANS TO MOVE THE PLATEN TOWARD THE WORK SUPPORT TO FORCE THE DIE THROUGH SHEET MATERIAL POSITIONED ON THE WORK SUPPORT, A SOLENOID OPERATED VALVE FOR SAID HYDRAULIC MEANS, AN ELECTRIC CIRCUIT CONTROLLING SAID VALVE, AN INERTIA SWITCH MOUNTED ON AND PHYSICALLY MOVABLE WITH SAID PLATEN AND SO ARRANGED THAT IT IS OPERATED BY INERTIA WHEN THE PLATEN CAUSES THE DIE TO BEGIN TO CUT THE MATERIAL, SAID SWITCH BEING SO CONNECTED IN SAID VALVE CONTROLLING CIRCUIT THAT OPERATION OF THE SWITCH REVERSES THE MOVEMENT OF THE PLATEN AFTER A SLIGHT DELAY ADEQUATE FOR THE DIE TO CUT THROUGH THE MATERIAL. 